Safety-valve and alarm



(No Model.)

T. SHAW.

SAFETY VALVE AND ALARM.

Patented Nov. 1, 1887.

v/ liv/, Y .As l

UNTTED STATES PATENT EETCE.

THOMAS SHA\V, OF PHILADELPHIA, PENNSYLVANIA.

SAFETY-VALVE AND ALARM.

SPECIFICATION forming part of Letters Patent No. 372,493, dated November 1, 1887.

Application filed September 8, 1885. Serial No. 176,476.

To @ZZ wtom it may concern:

Be it known that I, Trroims Sr-mw, of the city and county ofPhiladelphia, Pennsylvania, haveinvented a new and Improved Maximum- Pressure' Reliet'- Valve and High Pressure Alarm for Steam, Gas,or Hydraulic Pressures; and I hereby declare the following to be a full, clear, and exact description of the same, reference bei nghad to the accompanying drawings, and to the letters cf reference marked thereon.

My invention consists in the employment of a flat-faced valve without the usual valve-seat,

and of unalterable area of valve-surface to pressure, and in the provision of adiaphragm to prevent leakage through the valve and to prevent corrosion of the valve, and in the combination of a whistle or alarm, all arranged in the manner and for the purpose as hereinafter described.

The object of the invention is to furnish a special safet-yyalve and alarm that is certain of action and secure against leakage for all purposes of fluid or gas pressures, one that cannot corrode fast to its valveseat and eement itself immovably during long periods of inactivity; one that is sure to blow off at any predetermined pressure, and capable of giving alarm, if desired.

In order to enable others to use and practice my invention, I will proceed to describe its Construction and operation.

On reference to the accompanying drawings, which form part of the specification, Figure l represents a vertical section through the center of valve. Fig. 2 is a top View with springvalve, &e., removed.

Similar letters refer to similar parts, of which- Z is the main body or cylinder portion of valve, provided with a female thread on its under side for the reception of a stationary valve guide-ring, c, and screw attachment plug a, the valve k, consisting of a cylindrical body portion fitting the bored passage-way in the center of ring c, and terminating at its upper end in a flange, the guidebearings of said valve k being furnished by wings which projectinwardly from said ring c, as shown in Figs. l and 2. The lower edge of guidering c is turned to a sharp edge on its inner diame` (No model.)

ter, (shown at 19,) at the same angle shown in the solid or ring portion of said ring c. Said angle is provided for the ready escape ofsteam, &c., between the wings t', whenever said valve is caused .to blow off. The said flange at the upper end of the valve L is for the purpose of furnishing ,a rest or limiting its downward movement to the top of wings t', whichlocatcs the face of the valve in its proper position when in a state of rest. A central bearingplug, n, transmits load of spring c to said valvec. Asimilar plug, j", atthe top, receives any regulated pressure from screw cap g, which has a central pivot arranged to press upon said spring e, all for the purpose hereinafter described.

d is escape passageway for attachment of ordinary whistle or other suitable alarm, actuated by the escaping steam or gases. The screw-plugris intended, when set,to be screwed solid to the shoulder to prevent any alterations ofthe springpressure after the valve is once set.

A diaphragm of leadfoil is interposed between screW-plug a and the face of the guide or valve ring @,where it is secured tight against leakage by screwing tightly the plug a. A washer, ofsoft metal or of tanite, can be placed next to the plug a to take the frictional wear and to press into anyinequalitics ofthe faces. This diaphragm of lead-foil covers the intervening space or crevice between valve k and the guidering c, preventing any leakage of steam, &c., that may press upon the under side of said valve It', and at the same time prevents access of corrosive fluids, Jvc., to the face of valve 7c. The pipe b is connected with a steam-boiler or any source of pressure that is desired to limit the maximum pressure.

s is a metallic washer held in position by screw,(shown in center ofvalveh) which holds the lead diaphragm against the lower'end of valve k, preventing the destruction ofthe said diaphragm by any vacuum that may form on the under side.

The operation of valve is in this wisc: The screw cap g is screwed down to press upon spring c to any desired pressure ascertained by test trials or otherwise, which determines the length of said spring c, when said cap can be screwed firmly to the shoulder of cylinder IOO Z. The said lead-foil diaphragm is inserted and secured in place between guide-ringcand4 screw-plug a, as before described, when the valve is ready for use, and on applyingsteam or other pressure in the passage-way b up to the maximum point at which thel valve is set. The cutting-edge cuts any feeble resistance offered by the foil-diaphragm and at the same time lifts the valve, permitting the4 escape of steam through the passage-ways between the wlngs i, and out of the exit-passage d, in directlon indicated by arrows, to sound any whistle or other alarm or to blow off into the air, as desired, and to afford relief of pressure, the size of valve passage-ways, Src., being regulated by the demands made upon the same. It will be observed that the said valve 7c cornes down to a sharp edge where it meets the cylinder portion of guide-ring c at the diaphragm or face of valve. This minimum Contact of metal Asurfaces at the valve-face prevents any possible corrosive action from securing hold upon the valve, and avoids one ofthe principal dangers of the ordinary safety-valves, with large face-conv tact, subjected to corrosive action and possible cementation to its seat, which renders the valve dangerous, and therefore unreliable after any i large-faced conical safety-valve ot' oneinch bore and quarter-inch face. The face area in this case is equal to the bore, in which case, it'

the valve be ground tight into its'seat and set to one hundred pounds pressure on its small-4 v est area, the samevalve, if leaking, would blow oft' at fifty pounds pressure, on account of the increased area of valveface, doubling the working-area of the valve, which difficulty is entirely overcome in the described maXimun1- pressure valve.

The lead diaphragm is destroyed andrequired to be renewed every time the valve is permitted to blow off, the destruction of the said diaphragm being evidence that the valve has blownoff.

It will be evident that other metals or materials can be substituted for the lead-foil, and that the same valve can be controlled by the ordinary lever and weights, in place of' the spring, and that it can be variously modified in shape without any alteration in the result. I therefore do not wish to confine myself to the exact shape here given.

What I claim, and desire to secure by Letters Patent, is-

l. The combination of' the valve guide-ring having a beveled face and radial wings, and a valve fitting the` opening in the ring at the lower end and between the radial wings, substantially as described.

2. The combination of the valve guide-ring having a beveled face and inwardly-projecting wings, and a valv'e with a cylindrical body and top flange resting on said wings, and a spring bearing on the valve, substantially as described. t

-below the ring, substantially as described.

5. In combination with valve 7c and a friable diaphragm secu red thereto and stretched across the valve-opening, a disk or washer, s, whichr holds the diaphragm against the valve and operates to prevent destruction of vdiaphragm by back-pressure, substantially as described.

THOMAS SH AW.

Witnesses:

J. LOGAN Frr'rs, WM. GARwooD. 

